Hot Fruit Flies Have It Rough

Hot Fruit Flies Have It Rough

Why you should care

Knowing more about selection will lead to further understandings about evolution. 

It sounds like a stand-up routine, right? Sexual harassment is such a problem, even female insects have to beat the men off like flies! Cue canned laughter. Except, it’s not a joke. A study from the University of Queensland shows that it’s not only lady Homo sapiens who suffer from sexual attention of the excessive, uninvited variety:

Attractive female fruit flies suffer from sexual harassment.

Being hot isn’t all it’s cracked up to be, even if you’re a bug. The study, conducted by Australian and Canadian researchers and using 12 fruit fly populations, with 55 females and 55 males, found that in competitive settings — think high school dance —the really cute females got all the boys’ attention. Unfortunately, the males overdid their courtship. Because of the intensity of male ardor, female fruit flies ended up physically hurt, zapped of energy or unable to reproduce. This led the lab to conclude, rather sensibly, that attractiveness worked against natural selection.

First of all, what about a fruit fly female brings qualifies as “really cute”? It’s a mix of pheromones and fertility signals, like a swollen stomach. And why do we care? The lab was testing if natural and sexual selection work together or in opposition, says Steve Chenoweth, lead researcher. It’s like when Charles Darwin wondered why male peacocks had bright tail feathers. Could the same tail feathers that helped them attract females — evolutionary advantage — also attract predators, aka evolutionary buzzkill?

This research can also be used to help science as a whole understand how species adapt to their environments, Chenoweth says. Think of it as the preliminary step to knowing on a DNA level what genes are involved in these fruit fly interactions, which in the future can be used to optimize the chance of survival. Joanne Yew, an assistant professor at the Pacific Biosciences Research Center, says the study’s ideas are testable with other animals too, because of what she calls Chenoweth’s “well-designed” experimental method. The only downside of branching out is obvious: Getting results will take longer with animals with longer life spans.

Of course, these findings are part of an ongoing story. For one thing, Chenoweth thinks the results would be stronger with a sample size 10 times larger than what his team used. And over longer periods of time, Chenoweth says, they might see a different, more nuanced relationship between natural and sexual selection. Going forward, researchers are keen to answer other questions, like what specific biological processes and genes are at play. If the researchers can find out, Chenoweth says, they’ll know what genes “create the biggest bang for their buck.”

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